JILA, National Institute of Standards and Technology (NIST), and University of Colorado, and Department of Physics, University of Colorado, Boulder, CO 80309-0440, USA.
Science. 2013 Dec 6;342(6163):1220-2. doi: 10.1126/science.1243683.
Polar molecules are desirable systems for quantum simulations and cold chemistry. Molecular ions are easily trapped, but a bias electric field applied to polarize them tends to accelerate them out of the trap. We present a general solution to this issue by rotating the bias field slowly enough for the molecular polarization axis to follow but rapidly enough for the ions to stay trapped. We demonstrate Ramsey spectroscopy between Stark-Zeeman sublevels in (180)Hf(19)F(+) with a coherence time of 100 milliseconds. Frequency shifts arising from well-controlled topological (Berry) phases are used to determine magnetic g factors. The rotating-bias-field technique may enable using trapped polar molecules for precision measurement and quantum information science, including the search for an electron electric dipole moment.
极性分子是量子模拟和冷化学的理想体系。分子离子很容易被捕获，但施加于其上的偏置电场会将其加速出阱。我们通过缓慢旋转偏置场来解决这个问题，使得分子极化轴能够跟随旋转，但同时又足够快地使离子保持在阱中。我们在（180）Hf（19）F（+）中演示了斯塔克-塞曼子能级之间的拉姆齐光谱，相干时间为 100 毫秒。通过对受控拓扑（贝里）相位的频率移动的测量，我们可以确定磁 g 因子。旋转偏置场技术可以使囚禁的极性分子应用于精密测量和量子信息科学，包括电子电偶极矩的搜索。
